What engines are a direct drop in for a 91 X??

[BajaBilly]

I'm wondering if anyone would know what years would be an exact drop in replacement for a 1991 X with a 4.0 liter in it?

Or a possible lead where I can find this info would work also.

Thanks

 

[410Fortune]

A complete drop in 4.0L OHV from any year up to 94 will work. You just need to check a few things, make sure the donor has the same options as you.

The 93 and later 4.0L's have stronger head castings.

You may run into a few issue's/problems like:

in 1991 the OHV 4.0L has a single 02 sensor, after 92 they have dual 02 sensors

The 91 4.0L also has a different routing for the A/C and canister purge/charcoal canister, shouldnt be a problem but noted.

the 91 4.0L also has a MAP sensor, after 93 the MAP is gone.

Just some things to be aware of. If I was you i would look for a 94 OHV 4.0L to drop in, or just rebuild your 91 using the later model heads.

Your single 02 sensor setup will work , its just a computer issue. The big thing is to make sure your donor engine has or does not have EGr, obviously if your 91 is equipped with EGR you want a donor that has EGR.

When you get into using a OHV 4.0L from a 95 or later it will work there are just a few additional items to look out for, I guess the exhaust manifolds are different, motor mounts, and some other stuff. There is a ton of information about this situation posted on the 4.0L forum board over at www.therangerstation.com

Good Luck!!!!

 

[410Fortune]

Oh also the wiring for the alternators changed after 92 so you want to keep yours or re-wire for the later style alternator....I'msure there is more this is just off the top of my head....

 

[88vert]

something to look for

My 92 sport does not have egr and only has one o2 sensor

 

[410Fortune]

Thats right, in 93 the double 02 sensors appeared. Not all 92's have EGR.

You will find various setups for different years, it's like Ford used the parts off the shelves until they were out then went with the new stuff, like for example I have seen 90 BII's with D35 front axles, I have seen 90 BII's with 4.0L's from the factory, and I have seen 91 4.0L Explorer's with 2.9L dual fuel pump setups, so anything is possible. If you look at a 91 4.0L you will see a 2.9L style alterntor (wiring) with the 4.0L serpentine pully and mount, and you will see the A/C lines run exactly like a 2.9L, around the back of the upper intake, oh and the 91 4.0L's also use the small power distribution box with the relays under the box and it appears that some early 93's still had this setup, so who knows what's got what, it changes from truck to truck.....

All I know is my 88 BII has a little bit of everything fromalmost all years of Explorer's up to 98

 

[BajaBilly]

Man, that was quick!!!!

Thanks alot for the useful info 410Fortune.

I never realized there were so many issues just within the few years.
I'm going to have to find about my EGR, or if it has one.

I'm going to go and check out the info over at therangerstation right now.

Thanks again for the help!!!

 

[MR99si]

When you say direct drop in what do you mean specificly? You can run any ohv block and heads and run your stuff, intake manifold, exhaust manifolds etc...

This is what I am doing. I got a 99 ranger motor with 11k original miles for 850 bucks. I will be installing this as soon as my flywheel bolts come from ford. I had to get an 8 bolt flywheel and 6 more bolts since they wont just sell me 2. That is all you will need is the flywheel since yours is a 6 bolt. I know this will work because my uncle did the same two years ago or so.